Generally speaking, the multistage centrifugal pump has a plurality of impellers mounted on the same pump shaft, and the outer side of the impeller is a liquid guiding device and a pump casing. However, how to install the impeller group in the pump body or remove it from the pump body? There are two ways to do this. One is to divide the pump body and the flow guiding device horizontally along the axis of the pump shaft so that it becomes the upper and lower parts. It is called a horizontal split multistage centrifugal pump; the other method is to cut the pump body and the liquid guiding device in the direction of the pump axis between the impellers in a plane perpendicular to the pump axis into several segments. Stage centrifugal pump.
The pump adopts a volute-shaped pump body, and each impeller has a corresponding volute at the periphery thereof, which is equivalent to installing several single-stage volute pumps on the same shaft in series, so it is also called a volute multi-stage pump. . Since the pump body is horizontally split, the suction port and the discharge port are directly cast on the pump body, which is convenient for inspection. The entire rotor can be exposed by simply removing the pump cover. When the rotor is inspected, the entire rotor is required. It is not necessary to remove the connecting pipe when lifting. The impellers of such pumps are usually evenly symmetrically arranged, and most of the axial forces are balanced so that no axial balancing devices need to be installed. The horizontal split multistage pump has a flow range of 450 to 1500 m'/h and a maximum head of 1800 mHz0. Due to the symmetrical arrangement of the impeller and the cross flow passage in the pump casing, it is larger than the segmented multistage pump of the same performance, the casting process is complicated, the positioning of the pump cover and the pump body is high, and the pump cover is high when the pressure is high. It is difficult to seal with the joint surface of the pump body.
Structure of sectional multistage centrifugal pump
When the pressure is high, a multistage centrifugal pump is usually used. The pump is a vertically split multistage pump that has a front section, a tail section and a number of midsections that are joined together by four long rod bolts. The number of impellers mounted on the pump shaft represents the number of stages of the centrifugal pump. Each impeller in the middle section is equipped with a guide wheel. The role of the guide wheel is basically the same as that of the volute, mainly to convert kinetic energy into static pressure energy. The impeller is generally single-suction, and the suction population is oriented in one direction. In order to balance the axial force, a balance disc is placed behind the end section and connected to the front section inlet by a balance tube. The rotor can be tilted left and right along the axial direction during the working process, and the axial force of the impeller group is balanced by the thrust of the balance disc to maintain the rotor near the equilibrium position. Both ends of the shaft are supported by bearings and placed on the bearing housing, and shaft sealing devices are provided at both ends of the shaft.
